Author Topic: PBT vs ABS: discoloration / staining over time  (Read 10834 times)

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Offline Photoelectric

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PBT vs ABS: discoloration / staining over time
« on: Mon, 13 May 2013, 00:49:15 »
I'm curious which plastic stands up to prolonged use better in terms of discoloration.  Say I start out with a bright white legend set in ABS and PBT.  Will either of them yellow / darken faster?  Not talking about dirt that can be cleaned off.

And in terms of thick PBT sets in light colors, can I expect to see the key caps stay in like new condition for a couple years with careful moderate use?
« Last Edit: Mon, 13 May 2013, 00:51:08 by Photoelectric »
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Offline Jocelyn

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Re: PBT vs ABS: discoloration / staining over time
« Reply #1 on: Mon, 13 May 2013, 00:50:29 »
You will definitely want PBT if you're worried about yellowing or shiny caps :)

Edit: I should probably add that it has to do with PBT having better UV resistance, though I've read that a keyboard cover can help slow it down with both.
« Last Edit: Mon, 13 May 2013, 00:56:01 by Jocelyn »

Offline nsrexler

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Re: PBT vs ABS: discoloration / staining over time
« Reply #2 on: Mon, 13 May 2013, 08:53:29 »
PBT is much more resistant to yellowing than ABS. For example, take a look at old Model M keyboards. The case (made of ABS) is usually pretty significantly yellowed, whereas the keycaps (made of PBT) are usually pretty much their original color (after a quick cleaning of course.)

Offline Photoelectric

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Re: PBT vs ABS: discoloration / staining over time
« Reply #3 on: Mon, 13 May 2013, 09:11:31 »
Thank you both--I'll stick with PBT for anything light colored now.
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Offline Ninjerk

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Re: PBT vs ABS: discoloration / staining over time
« Reply #4 on: Sun, 19 May 2013, 22:52:45 »
I work in an environment where we still use Model M boards daily.

Most of these boards are 20+ years old, but the keycaps on them still look much much better than the ones on the logitech wireless keyboards we've been using on our PC systems for the last 6 months - they're already shiny and smooth in some parts.

Offline Jocelyn

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Re: PBT vs ABS: discoloration / staining over time
« Reply #5 on: Sun, 19 May 2013, 23:21:00 »
I work in an environment where we still use Model M boards daily.

Most of these boards are 20+ years old, but the keycaps on them still look much much better than the ones on the logitech wireless keyboards we've been using on our PC systems for the last 6 months - they're already shiny and smooth in some parts.

Lol, I think this really really sums it up :)

Offline Photoelectric

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Re: PBT vs ABS: discoloration / staining over time
« Reply #6 on: Sun, 19 May 2013, 23:33:18 »
I'm definitely getting thick PBT caps for daily usage.  But I do hope the Lily DS set takes off, because it sure is pretty... Even though it has white ABS caps that Ill end up trying to not breathe on :)
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Offline tp4tissue

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Re: PBT vs ABS: discoloration / staining over time
« Reply #7 on: Tue, 21 May 2013, 11:23:40 »
just BEING pbt doesn't make it less prone to yellowing..  Legos for example NEVER changed colors despite being abs

Too many other factors involved, the best you can do cross fingers and pray...

This PBT fanboyism has to stop...

Offline Findecanor

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Re: PBT vs ABS: discoloration / staining over time
« Reply #8 on: Tue, 21 May 2013, 14:47:53 »
Most of the yellowing is from brominated flame retardants in the ABS plastics. Not all formulas for ABS plastic contains it, but is common for plastic used for electronic products.
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Offline TotalChaos

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Re: PBT vs ABS: discoloration / staining over time
« Reply #9 on: Tue, 21 May 2013, 19:37:35 »
It all depends what they throw into the vat when they brew up the plastic.  The PlasticsWizards can throw in UV Protection or the opposite.
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Offline 1391406

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Re: PBT vs ABS: discoloration / staining over time
« Reply #10 on: Tue, 21 May 2013, 22:42:21 »
Most of the Model M cases I've seen don't seem to have much yellowing at all.

Are there any cases made out of PBT?
« Last Edit: Wed, 22 May 2013, 06:05:34 by 1391406 »
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Offline Kurk

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Re: PBT vs ABS: discoloration / staining over time
« Reply #11 on: Thu, 23 May 2013, 01:14:49 »
just BEING pbt doesn't make it less prone to yellowing..  Legos for example NEVER changed colors despite being abs

Too many other factors involved, the best you can do cross fingers and pray...

This PBT fanboyism has to stop...
Oh? I've got hundreds of yellowed white LEGO bricks. In fact, AFOLs were discussing bleaching LEGO way before that subject arrived in the keyboard community.

Offline Photoelectric

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Re: PBT vs ABS: discoloration / staining over time
« Reply #12 on: Thu, 23 May 2013, 01:28:00 »
Some more specific case questions on the topic:

Filco white ABS stock caps: good? average? 

A lot of the vintage keys I see in photos, like old Cherry and maybe like Dolch have this nice thick and shiny appearance.  They are not both PBT, right?  Maybe photos are just deceptive, and quality PBT and double-shot ABS converge in appearance after years of use.  I just keep thinking how nice those caps look. 
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Offline nsrexler

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Re: PBT vs ABS: discoloration / staining over time
« Reply #13 on: Thu, 23 May 2013, 09:20:37 »
Most of the Model M cases I've seen don't seem to have much yellowing at all.

Are there any cases made out of PBT?

As I understand it, PBT becomes much harder to work with as size increases. That's why PBT spacebars are frequently misshapen.

Offline Jocelyn

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Re: PBT vs ABS: discoloration / staining over time
« Reply #14 on: Thu, 23 May 2013, 09:21:29 »
Most of the Model M cases I've seen don't seem to have much yellowing at all.

Are there any cases made out of PBT?

As I understand it, PBT becomes much harder to work with as size increases. That's why PBT spacebars are frequently misshapen.

You mean warped? It's very easy to straighten them :)

Offline nsrexler

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Re: PBT vs ABS: discoloration / staining over time
« Reply #15 on: Thu, 23 May 2013, 13:42:32 »
Most of the Model M cases I've seen don't seem to have much yellowing at all.

Are there any cases made out of PBT?

As I understand it, PBT becomes much harder to work with as size increases. That's why PBT spacebars are frequently misshapen.

You mean warped? It's very easy to straighten them :)

Well some I've seen also have a faintly "rippled" shape to them, which is harder to fix. Anyway, my point was that making something as large as a keyboard case out of PBT would probably cause a lot of headaches in manufacturing.

Offline 1391406

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Re: PBT vs ABS: discoloration / staining over time
« Reply #16 on: Thu, 23 May 2013, 18:55:14 »
I read that the Leopold FC700RT has a PBT case.
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Offline nsrexler

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Re: PBT vs ABS: discoloration / staining over time
« Reply #17 on: Thu, 23 May 2013, 19:26:44 »
I read that the Leopold FC700RT has a PBT case.

Interesting, I didn't know that. Do you know of any other keyboards with PBT cases? The main reason I ask is because I tend to rest my fingers above the arrow keys and so my keyboards gradually get wear marks there.

Offline 1391406

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Re: PBT vs ABS: discoloration / staining over time
« Reply #18 on: Fri, 24 May 2013, 06:27:49 »
I read that the Leopold FC700RT has a PBT case.

Interesting, I didn't know that. Do you know of any other keyboards with PBT cases? The main reason I ask is because I tend to rest my fingers above the arrow keys and so my keyboards gradually get wear marks there.

I believe someone had mentioned that the current Deck Legend series is made of PBT.
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Offline Grim Fandango

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Re: PBT vs ABS: discoloration / staining over time
« Reply #19 on: Fri, 24 May 2013, 18:47:19 »
I really dislike the look of the yellowing on ABS keycaps. Since I always sit next to a window, both at work as well as at home, I have to take into account that the keyboards are going to practically have sunlight almost directly on them for most of the day. Since I am a big fan of white keycaps, I had to go PBT. When it comes to developing shine, I actually found that on black keycaps it is much more noticeable then on lighter colors. Though not having shine develop fast with PBT is till nice.
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